python的udp的socket

apple:udp apple$ cat UDPClient.py 
#!/usr/bin/env python
"USAGE: %s <server> <word> <port>"
from socket import *    # import *, but we'll avoid name conflict
from sys import argv, exit
if len(argv) != 4:
    print __doc__ % argv[0]
    exit(0)
sock = socket(AF_INET, SOCK_DGRAM)
messout = argv[2]
sock.sendto(messout, (argv[1], int(argv[3])))
messin, server = sock.recvfrom(255)
if messin != messout:
    print "Failed to receive identical message"
print "Received:", messin
sock.close()
apple:udp apple$ 

apple:udp apple$ cat UDPServer.py 
#!/usr/bin/env python
"USAGE: %s <port>"
from SocketServer import DatagramRequestHandler, UDPServer
from sys import argv

class EchoHandler(DatagramRequestHandler):
    def handle(self):
        print "Client connected:", self.client_address
        message = self.rfile.read()
        self.wfile.write(message)

if len(argv) != 2:
    print __doc__ % argv[0]
else:
    UDPServer(('',int(argv[1])), EchoHandler).serve_forever()
apple:udp apple$